CHARLOTTE — Vijay Singh learned Tuesday before a practice round for the Wells Fargo Championship that he had been cleared of a doping violation by the PGA Tour.

Singh, a member of the World Golf Hall of Fame who counts three major championships among his 34 Tour victories, admitted in January in an interview with Sports Illustrated to using deer-antler spray but was unaware that it could contain a banned performance-enhancer connected to human growth hormone called Insulin-like Growth Factor-1 (IGF-1).

But information supplied by the World Anti-Doping Agency (WADA) during the Tour's investigation says the use of deer antler spray is no longer prohibited. Based on that information, PGA Tour Commissioner Tim Finchem, speaking Tuesday at Quail Hollow Club, decided to drop the case.

Singh, through a Tour spokesperson, declined comment. This week's Wells Fargo Championship will be Singh's seventh Tour start since the news of his admission broke during the Waste Management Phoenix Open.

Singh was sanctioned by the Tour on Feb. 19 because his admission violated the Tour's Anti-Doping policy, which closely follows the International Anti-Doping Standard established by WADA. Seven days later, Singh appealed the sanction and the Tour's investigation continued.

The Tour, which confirmed that the deer-antler spray that Singh used contained IGF-1, contacted WADA and was told the organization had clarified its position on deer-antler spray.

"In relation to your pending IGF-1 matter, it is the position of WADA, in applying the Prohibited List, that the use of "deer antler spray" (which is known to contain small amounts of IGF-I) is not considered prohibited," WADA said in a written correspondence with the Tour. "On the other hand it should be known that Deer Antler Spray contains small amounts of IGF-1 that may affect anti-doping tests. Players should be warned that in the case of a positive test for IGF-1, it would be considered an Adverse Analytical Finding."

Singh, 50, violated the Tour's policy by admitting he had taken the banned substance, not by a drug test. There is no routine blood test available to detect IGF-1, and WADA and other medical experts have determined that only traces of a human growth hormone called IGF-1 would enter the body through a spray. The Tour was told of WADA's new information last Friday.

"We follow WADA on this stuff," Finchem said. "We refer to them and defer to them on the science of these issues as to what's on the list. The fact of the matter here is, as some people in the medical community pointed out when this matter came up, and now science at WADA has looked into it and concluded on their own, it's just not worth having it on the list in that context.

" … I don't think you can move ahead with a prosecution on a player given this set of facts. That's our conclusion. Because, again, Vijay wasn't assessed this action because he was negligent. He wasn't assessed it because he made a mistake. He was assessed it because he violated the Doping Code, and the Doping Code is predicated on a list of substances. And we're now finding from WADA that that substance doesn't trigger a positive test to admission, so we have to respect that."

In the end, Singh won't even be sanctioned for admitting to taking what was then a banned substance. While that remains a direct violation of the Tour's doping policy, it is unclear what grounds Singh and his lawyers appealed the initial sanction. Finchem would not divulge that information.

"Well, they had a variety of arguments," Finchem said. "Anytime you get a couple lawyers involved, they're going to come up with plenty of arguments."

Finchem added he is not worried about negative reaction to the Tour's decision. When asked if he was concerned that some people would think Singh was cleared on a technicality, Finchem said no.

"I don't think so for two reasons," he said. "One: I think that people who pay attention to the facts here will conclude or come to the same conclusion that I found with a lot of people. You get into one of these things and everybody wants to talk to you about it. I thought that the fairly strong attitude among people that if it's a violation, we don't have any choice here. It's not like we have discretion. We have to take action that the deer antler spray is a harmless situation, I think that is the general attitude. Apparently that's what WADA has concluded.

"I think the other thing is I just think people generally have a very strong view of the integrity of our players. I think it's going to take a lot to shake the foundation of what players have spent decades to build, and this, I don't think, fits the bill."